McDonald's hamburgers make me sick?

I don't eat McDonald's very often, but a few hours after eating a hamburger I started feeling sick. This is the second time I felt sick after eating a quarter pounder. (I can't even finish the whole burger) The only reason we even went there because we were in a hurry and had a coupon. Last time I had a burger from there I felt the exactly the same. It's all in the stomach. Anyone else have this issue?